[Backport 6.2] fix(bucket-locations): add templating to backup_bucket_location

[scylladbbot]

since now we are doing backup/restore in the test region and backup_bucket_region was remove.

the code for this configuration need to be templated as it was done for restore nemesis

otherwise we fail like the following:

23:22:43  Command: 'sudo sctool backup -c a05d9ea2-312c-4c8d-99b0-9f9b57e8cbde
          --keyspace scylla_bench,keyspace1  --location s3:manager-backup-tests-us-east-1 '
23:22:43  Exit code: 1
23:22:43  Stdout:
23:22:43  Stderr:
23:22:43  Error: create backup target: location is not accessible
23:22:43  10.4.2.70: agent [HTTP 400] operation put: s3 upload: 301 Moved Permanently:
          The bucket you are attempting to access must be addressed using the specified endpoint.
          Please send all future requests to this endpoint. (code:PermanentRedirect) - make sure the location
          is correct and credentials are set, to debug SSH to 10.4.2.70 and run
          "scylla-manager-agent check-location -L s3:manager-backup-tests-us-east-1 --debug"
23:22:43  Trace ID: DXvyKGPjQMKUCkJpyxlKCQ (grep in scylla-manager logs)

Testing

• 🕐 https://jenkins.scylladb.com/job/scylla-staging/job/fruch/job/longevity-100gb-4h-test/97/

PR pre-checks (self review)

• I added the relevant backport labels
• I didn't leave commented-out/debugging code

Reminders

• Add New configuration option and document them (in sdcm/sct_config.py)

• Add unit tests to cover my changes (under unit-test/ folder)

• Update the Readme/doc folder relevant to this change (if needed)

• (cherry picked from commit fe55645)

Parent PR: #9788

[scylladbbot]

@fruch - This PR has conflicts, therefore it was moved to draft
Please resolve them and mark this PR as ready for review